Star Bridge

The galaxy’s inhabited planets are held together by the repressive Eron Company, the apparent holder of the secret to faster–than–light travel through the Tubes, the network linking the scattered worlds together. Mysterious parties have hired the adventurer Horn to assassinate the company's general manager, Garth Kohlnar. Horn completes his mission, and in the ensuing manhunt encounters Wendre Kohlnar, the daughter and now possibly the heir of the dead man.
Escaping through a transdimensional Tube, Horn finds himself on the planet Eron, a world consumed by the Eron Company. There he encounters a corrupt aristocracy, a brewing power struggle over the succession, a covert revolution, and the mystery of who actually knows the secret of the Tubes.
James Gunn and Jack Williamson's Star Bridge marks the return of a classic, high-concept space opera by two SF Grand Masters